Software gives scientists animal-eye view of the world

By Edd Gent

Published Friday, August 7, 2015

Software that converts digital photos into representations of animal vision could offer new insight into animal and plant signalling and camouflage.

While humans and most primates have eyes sensitive to red, green and blue light, many mammals are only sensitive to blue and yellow, while most birds, reptiles, amphibians and many insects see in four or more and are also sensitive to the ultraviolet range invisible to humans.

Converting digital images to represent animal vision has previously had to be done manually, but now researchers at the University of Exeter have created open source software that lets scientists calibrate their images, incorporate multiple layers - such as visible and UV channels -, convert to animal colour spaces, and measure images easily.

"Viewing the world through the eyes of another animal has now become much easier thanks to our new software," said Jolyon Troscianko, first author of a paper on the software published in journal Methods in Ecology & Evolution.

"Digital cameras are powerful tools for measuring colours and patterns in nature but until now it has been surprisingly difficult to use digital photos to make accurate and reliable measurements of colour.

"Our software allows us to calibrate images and convert them to animal vision, so that we can measure how the scene might look to humans and non-humans alike. We hope that other scientists will use this open access software to help with their digital image analysis."

To use the software researchers must use a camera converted to full spectrum sensitivity. By taking one photograph through a visible-pass filter and another through an ultraviolet-pass filter the two can be combined in the software to show the image through an animal's eyes.

In their paper the researchers have provided specific data on camera settings for commonly studied animals, such as humans, blue tits, peafowl, honey bees, ferrets and some fish.

The university's Sensory Ecology group has already used the software to investigate colour change in green shore crabs, tracking human female face colour changes through the ovulation cycle, and determining the aspects of camouflage that protect nightjar clutches from being spotted by potential predators.